All of lore.kernel.org
 help / color / mirror / Atom feed
From: Greg KH <gregkh@linuxfoundation.org>
To: Zheng Wang <zyytlz.wz@163.com>
Cc: hackerzheng666@gmail.com, 1002992920@qq.com, airlied@linux.ie,
	alex000young@gmail.com, dri-devel@lists.freedesktop.org,
	intel-gfx@lists.freedesktop.org, jani.nikula@linux.intel.com,
	linux-kernel@vger.kernel.org, security@kernel.org,
	tvrtko.ursulin@linux.intel.com
Subject: Re: [PATCH] drm/i915/gvt: fix double free bug in split_2MB_gtt_entry
Date: Sun, 2 Oct 2022 16:18:27 +0200	[thread overview]
Message-ID: <Yzmds3DXu32EeSO5@kroah.com> (raw)
In-Reply-To: <20220928033340.1063949-1-zyytlz.wz@163.com>

On Wed, Sep 28, 2022 at 11:33:40AM +0800, Zheng Wang wrote:
> If intel_gvt_dma_map_guest_page failed, it will call
> ppgtt_invalidate_spt, which will finally free the spt.
> But the caller does not notice that, it will free spt again in error path.
> 
> Fix this by only freeing spt in ppgtt_invalidate_spt in good case.
> 
> Fixes: b901b252b6cf ("drm/i915/gvt: Add 2M huge gtt support")
> Reported-by: Zheng Wang <hackerzheng666@gmail.com>
> Signed-off-by: Zheng Wang <zyytlz.wz@163.com>
> ---
>  drivers/gpu/drm/i915/gvt/gtt.c | 16 +++++++++-------
>  1 file changed, 9 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/gvt/gtt.c b/drivers/gpu/drm/i915/gvt/gtt.c
> index ce0eb03709c3..550519f0acca 100644
> --- a/drivers/gpu/drm/i915/gvt/gtt.c
> +++ b/drivers/gpu/drm/i915/gvt/gtt.c
> @@ -959,7 +959,7 @@ static inline int ppgtt_put_spt(struct intel_vgpu_ppgtt_spt *spt)
>  	return atomic_dec_return(&spt->refcount);
>  }
>  
> -static int ppgtt_invalidate_spt(struct intel_vgpu_ppgtt_spt *spt);
> +static int ppgtt_invalidate_spt(struct intel_vgpu_ppgtt_spt *spt, int is_error);

That is a horrible way to make an api (and it should be a bool too.)

Now every time you see this call in the code, you have to go look up
what the last parameter means.  Just make 2 functions, one that does the
"is error" thing, and one that does not, and that will be much easier to
maintain and understand for the next 10+ years.

thanks,

greg k-h

WARNING: multiple messages have this Message-ID (diff)
From: Greg KH <gregkh@linuxfoundation.org>
To: Zheng Wang <zyytlz.wz@163.com>
Cc: alex000young@gmail.com, security@kernel.org,
	tvrtko.ursulin@linux.intel.com, airlied@linux.ie,
	intel-gfx@lists.freedesktop.org, hackerzheng666@gmail.com,
	dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org,
	1002992920@qq.com
Subject: Re: [PATCH] drm/i915/gvt: fix double free bug in split_2MB_gtt_entry
Date: Sun, 2 Oct 2022 16:18:27 +0200	[thread overview]
Message-ID: <Yzmds3DXu32EeSO5@kroah.com> (raw)
In-Reply-To: <20220928033340.1063949-1-zyytlz.wz@163.com>

On Wed, Sep 28, 2022 at 11:33:40AM +0800, Zheng Wang wrote:
> If intel_gvt_dma_map_guest_page failed, it will call
> ppgtt_invalidate_spt, which will finally free the spt.
> But the caller does not notice that, it will free spt again in error path.
> 
> Fix this by only freeing spt in ppgtt_invalidate_spt in good case.
> 
> Fixes: b901b252b6cf ("drm/i915/gvt: Add 2M huge gtt support")
> Reported-by: Zheng Wang <hackerzheng666@gmail.com>
> Signed-off-by: Zheng Wang <zyytlz.wz@163.com>
> ---
>  drivers/gpu/drm/i915/gvt/gtt.c | 16 +++++++++-------
>  1 file changed, 9 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/gvt/gtt.c b/drivers/gpu/drm/i915/gvt/gtt.c
> index ce0eb03709c3..550519f0acca 100644
> --- a/drivers/gpu/drm/i915/gvt/gtt.c
> +++ b/drivers/gpu/drm/i915/gvt/gtt.c
> @@ -959,7 +959,7 @@ static inline int ppgtt_put_spt(struct intel_vgpu_ppgtt_spt *spt)
>  	return atomic_dec_return(&spt->refcount);
>  }
>  
> -static int ppgtt_invalidate_spt(struct intel_vgpu_ppgtt_spt *spt);
> +static int ppgtt_invalidate_spt(struct intel_vgpu_ppgtt_spt *spt, int is_error);

That is a horrible way to make an api (and it should be a bool too.)

Now every time you see this call in the code, you have to go look up
what the last parameter means.  Just make 2 functions, one that does the
"is error" thing, and one that does not, and that will be much easier to
maintain and understand for the next 10+ years.

thanks,

greg k-h

WARNING: multiple messages have this Message-ID (diff)
From: Greg KH <gregkh@linuxfoundation.org>
To: Zheng Wang <zyytlz.wz@163.com>
Cc: alex000young@gmail.com, security@kernel.org, airlied@linux.ie,
	intel-gfx@lists.freedesktop.org, hackerzheng666@gmail.com,
	dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org,
	1002992920@qq.com
Subject: Re: [Intel-gfx] [PATCH] drm/i915/gvt: fix double free bug in split_2MB_gtt_entry
Date: Sun, 2 Oct 2022 16:18:27 +0200	[thread overview]
Message-ID: <Yzmds3DXu32EeSO5@kroah.com> (raw)
In-Reply-To: <20220928033340.1063949-1-zyytlz.wz@163.com>

On Wed, Sep 28, 2022 at 11:33:40AM +0800, Zheng Wang wrote:
> If intel_gvt_dma_map_guest_page failed, it will call
> ppgtt_invalidate_spt, which will finally free the spt.
> But the caller does not notice that, it will free spt again in error path.
> 
> Fix this by only freeing spt in ppgtt_invalidate_spt in good case.
> 
> Fixes: b901b252b6cf ("drm/i915/gvt: Add 2M huge gtt support")
> Reported-by: Zheng Wang <hackerzheng666@gmail.com>
> Signed-off-by: Zheng Wang <zyytlz.wz@163.com>
> ---
>  drivers/gpu/drm/i915/gvt/gtt.c | 16 +++++++++-------
>  1 file changed, 9 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/gvt/gtt.c b/drivers/gpu/drm/i915/gvt/gtt.c
> index ce0eb03709c3..550519f0acca 100644
> --- a/drivers/gpu/drm/i915/gvt/gtt.c
> +++ b/drivers/gpu/drm/i915/gvt/gtt.c
> @@ -959,7 +959,7 @@ static inline int ppgtt_put_spt(struct intel_vgpu_ppgtt_spt *spt)
>  	return atomic_dec_return(&spt->refcount);
>  }
>  
> -static int ppgtt_invalidate_spt(struct intel_vgpu_ppgtt_spt *spt);
> +static int ppgtt_invalidate_spt(struct intel_vgpu_ppgtt_spt *spt, int is_error);

That is a horrible way to make an api (and it should be a bool too.)

Now every time you see this call in the code, you have to go look up
what the last parameter means.  Just make 2 functions, one that does the
"is error" thing, and one that does not, and that will be much easier to
maintain and understand for the next 10+ years.

thanks,

greg k-h

  reply	other threads:[~2022-10-02 14:17 UTC|newest]

Thread overview: 93+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-18 19:24 [PATCH] drm/i915/gvt: fix double-free bug in split_2MB_gtt_entry Zheng Wang
2022-09-18 19:24 ` [Intel-gfx] " Zheng Wang
2022-09-19  9:30 ` Jani Nikula
2022-09-19  9:30   ` [Intel-gfx] " Jani Nikula
2022-09-19  9:55   ` Zheng Hacker
2022-09-19  9:55     ` [Intel-gfx] " Zheng Hacker
2022-09-19  9:55     ` Zheng Hacker
2022-09-21  9:13   ` Zheng Hacker
2022-09-21  9:13     ` [Intel-gfx] " Zheng Hacker
2022-09-21  9:13     ` Zheng Hacker
2022-09-28  3:33     ` [PATCH] drm/i915/gvt: fix double free " Zheng Wang
2022-09-28  3:33       ` [Intel-gfx] " Zheng Wang
2022-09-28  3:33       ` Zheng Wang
2022-10-02 14:18       ` Greg KH [this message]
2022-10-02 14:18         ` [Intel-gfx] " Greg KH
2022-10-02 14:18         ` Greg KH
2022-10-03  4:36         ` Zheng Hacker
2022-10-03  4:36           ` [Intel-gfx] " Zheng Hacker
2022-10-03  4:36           ` Zheng Hacker
2022-10-06 16:58       ` [PATCH v2] " Zheng Wang
2022-10-06 16:58         ` [Intel-gfx] " Zheng Wang
2022-10-06 16:58         ` Zheng Wang
2022-10-06 19:23         ` Greg KH
2022-10-06 19:23           ` [Intel-gfx] " Greg KH
2022-10-06 19:23           ` Greg KH
2022-10-07  0:39           ` Zheng Hacker
2022-10-07  0:39             ` [Intel-gfx] " Zheng Hacker
2022-10-07  0:39             ` Zheng Hacker
2022-10-07  1:37           ` [PATCH v3] " Zheng Wang
2022-10-07  1:37             ` [Intel-gfx] " Zheng Wang
2022-10-07  1:37             ` Zheng Wang
2022-10-27  0:01             ` [Intel-gfx] " Dave Airlie
2022-10-27  0:01               ` Dave Airlie
2022-10-27  0:01               ` Dave Airlie
2022-10-27  3:26               ` Zheng Hacker
2022-10-27  3:26                 ` [Intel-gfx] " Zheng Hacker
2022-10-27  3:26                 ` Zheng Hacker
2022-10-27  5:12                 ` Dave Airlie
2022-10-27  5:12                   ` [Intel-gfx] " Dave Airlie
2022-10-27  5:12                   ` Dave Airlie
2022-10-30 15:10                   ` Zheng Hacker
2022-10-30 15:10                     ` [Intel-gfx] " Zheng Hacker
2022-10-30 15:10                     ` Zheng Hacker
2022-12-15 10:47                   ` Joonas Lahtinen
2022-12-15 10:47                     ` [Intel-gfx] " Joonas Lahtinen
2022-12-15 11:33                     ` Wang, Zhi A
2022-12-15 11:33                       ` [Intel-gfx] " Wang, Zhi A
2022-12-15 13:26                       ` Zheng Hacker
2022-12-15 13:26                         ` [Intel-gfx] " Zheng Hacker
2022-12-15 13:26                         ` Zheng Hacker
2022-12-19  7:57                       ` [Intel-gfx] " Zheng Wang
2022-12-19  7:57                         ` Zheng Wang
2022-12-19  7:57                         ` Zheng Wang
2022-12-19  8:22                         ` Wang, Zhi A
2022-12-19  8:22                           ` Wang, Zhi A
2022-12-19  8:22                           ` Wang, Zhi A
2022-12-19  9:21                           ` Zheng Wang
2022-12-19  9:21                             ` Zheng Wang
2022-12-19  9:21                             ` Zheng Wang
2022-12-19 12:46                           ` [PATCH v4] [PATCH v4] " Zheng Wang
2022-12-19 12:46                             ` [Intel-gfx] " Zheng Wang
2022-12-19 12:46                             ` Zheng Wang
2022-12-19 12:52                           ` [RESEND PATCH " Zheng Wang
2022-12-19 12:52                             ` [Intel-gfx] " Zheng Wang
2022-12-19 12:52                             ` Zheng Wang
2022-12-20  8:22                             ` Zhenyu Wang
2022-12-20  8:22                               ` [Intel-gfx] " Zhenyu Wang
2022-12-20  8:22                               ` Zhenyu Wang
2022-12-20  9:03                               ` Zheng Hacker
2022-12-20  9:03                                 ` [Intel-gfx] " Zheng Hacker
2022-12-20  9:03                                 ` Zheng Hacker
2022-12-20  9:40                           ` [PATCH v5] " Zheng Wang
2022-12-20  9:40                             ` [Intel-gfx] " Zheng Wang
2022-12-20  9:40                             ` Zheng Wang
2022-12-21  2:58                             ` Zhenyu Wang
2022-12-21  2:58                               ` [Intel-gfx] " Zhenyu Wang
2022-12-21  2:58                               ` Zhenyu Wang
2022-12-21  5:01                               ` Zheng Hacker
2022-12-21  5:01                                 ` [Intel-gfx] " Zheng Hacker
2022-12-21  5:01                                 ` Zheng Hacker
2022-12-29 16:56                           ` [PATCH v6] " Zheng Wang
2022-12-29 16:56                             ` [Intel-gfx] " Zheng Wang
2022-12-29 16:56                             ` Zheng Wang
2022-09-19 20:17 ` [Intel-gfx] ✗ Fi.CI.BUILD: failure for drm/i915/gvt: fix double-free bug in split_2MB_gtt_entry (rev2) Patchwork
2022-09-29 18:16 ` [Intel-gfx] ✗ Fi.CI.CHECKPATCH: warning for drm/i915/gvt: fix double-free bug in split_2MB_gtt_entry (rev3) Patchwork
2022-09-29 18:40 ` [Intel-gfx] ✓ Fi.CI.BAT: success " Patchwork
2022-09-30 18:41 ` [Intel-gfx] ✓ Fi.CI.IGT: " Patchwork
2022-10-10 15:00 ` [Intel-gfx] ✗ Fi.CI.CHECKPATCH: warning for drm/i915/gvt: fix double-free bug in split_2MB_gtt_entry (rev5) Patchwork
2022-10-10 15:30 ` [Intel-gfx] ✗ Fi.CI.BAT: failure " Patchwork
2022-12-22 12:25 ` [Intel-gfx] ✗ Fi.CI.CHECKPATCH: warning for drm/i915/gvt: fix double-free bug in split_2MB_gtt_entry (rev8) Patchwork
2022-12-22 12:53 ` [Intel-gfx] ✓ Fi.CI.BAT: success " Patchwork
2022-12-22 18:13 ` [Intel-gfx] ✗ Fi.CI.IGT: failure " Patchwork
2022-12-29 17:57 ` [Intel-gfx] ✗ Fi.CI.BAT: failure for drm/i915/gvt: fix double-free bug in split_2MB_gtt_entry (rev9) Patchwork

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=Yzmds3DXu32EeSO5@kroah.com \
    --to=gregkh@linuxfoundation.org \
    --cc=1002992920@qq.com \
    --cc=airlied@linux.ie \
    --cc=alex000young@gmail.com \
    --cc=dri-devel@lists.freedesktop.org \
    --cc=hackerzheng666@gmail.com \
    --cc=intel-gfx@lists.freedesktop.org \
    --cc=jani.nikula@linux.intel.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=security@kernel.org \
    --cc=tvrtko.ursulin@linux.intel.com \
    --cc=zyytlz.wz@163.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.